1. Field of the Invention
The present invention relates to novel derivatives of benzoquinonylphenyl alkanoic acid amides and pharmaceutically acceptable salts thereof, and a cerebral insufficiency improver containing the same. These compounds can be widely utilized because they are effective for ameliorating and curing (or treating) various symptoms based on "cerebral organic disorders" and "pathergasia".
The term "cerebral organic disorders" used herein means various symptoms derived from cerebral ischemic diseases such as cerebral infarct sequela, cerebral hemorrhage sequela, and cerebral arteriosclerosis sequela and various organic disorders derived from senile dementia, dementia presenilis, amnesia, cephalic traumatic sequela, and cerebral operation sequela. Furthermore, the term "pathergasia" used herein means psychogender organic diseases derived from mania, melancholia, neurosis, Parkinson's disease, schizophrenia, schizophrenia-like disorders, and chorea (Huntington's chorea) as well as medicines and alcoholic beverages.
2. Description of the Related Art
Cerebral cells retain their own intracellular environments which are completely different from the surrounding environments, i.e., extracellular fluids, and while this difference is maintained, the cerebral cells are alive. Accordingly, energy must be always generated and supplied to cerebral cells. Most of the energy required by cerebral nerve cells is supplied by oxygen and glucose. These energy sources are not substantially stored in the brain and, therefore, are always supplied from the blood.
If certain cerebral disturbances or disorders occur, and if the supply of oxygen and glucose to the brain is stopped, generally there is a gradual or stepwise degression in energy metabolism. As a result, the cells lose their functions with the elapse of time, and the cells are soon organically broken. Thus, the cerebral cells cannot effect their normal functions. Therefore, a mechanism to adjust cerebral bloodstreams in the cerebral blood vessels themselves has been fully developed to stably supply the energy sources to the cerebral tissues and to maintain the outer environments of cerebral nerve cells.
Various cerebral circulating improvers, cerebral vasodilators, and cerebral excitometabolites have been heretofore used for the medical treatment of cerebral blood vessel disorders. But, although these medicines are effective for ameliorating subjective symptoms, no substantial amelioration of neutral symptoms and mental symptoms has been observed.
On the other hand, Japanese Unexamined Patent Publication (Kokai) No. 61-44840 discloses various derivatives of benzoquinonyl alkanoic acids, which are described as effective as an antiasthmatic agent, an antiallergic agent or a cerebral circulating improver.